My understanding is that when an interim construction loan is modified to a permanent loan, it is reported as a purchase. What would be the application date reported? I thought it would be the date the loan was modified to become permanent but I can't find that in any guidance material. What would be the application date?

The FRB did state in a training webinar (and confirmed via email when I contacted them) that a mod to perm is reportable while a mod for refi is not (which is what all statements on mods refer to - mods at time of refinance). If the borrower only applied one time for the construction and permanent financing, report the original date.